Thanks... I see what you mean, but at the moment I am not using any plugin to perform the spell check, so the fix doesn't solve the issue. The spell check feature is just included in W.P 2.8.4 and I believe uses the google api..according to this..

However, the spell checker that wordpress uses for all its own hosted sites is called 'After the Deadline'. This isn't included as standard in self hosted sites like mine but there is an 'after the deadline' plug in that I could use which would mean the spell checker would then be operating from the plugin folder, making your fix work.

I'm happy to try this out as a work around, but if you'd rather solve the original spellcheck issue without implementing the plugin then I'm happy to keep trying.